Assessment Of Acute Pulmonary Embolism And Global Right Ventricular Function With Dual Source CT

Objective The purpose of the study is to evaluate the clinical application of triggering position located at superior vena cava (SVC) and choose the different post-processing techniques in CT pulmonary angiography (CTPA).Materials and Methods Forty patients suspected of pulmonary embolism (PE) were divided into group A and B. For group A, the region of interest (ROI) of triggering position was located at pulmonary artery trunk (PAT), the threshold of triggering was 80 HU and the dose of contrast medium was 50-60 ml. For group B, The ROI was located at SCV, the dose of contrast medium was 35-45 ml, and other parameters were as same as group A. The quality of CTPA images in the two techniques was analyzed by two radiologists, and their results were in consensus. Densities of PAT and right lower pulmonary vein (RLFV) were measured, the displaying ratio of the 6th grade pulmonary artery was calculated, and the results were statistically analyzed. A P value<0.05 was considered statistically significant. The displaying radios of different post-processing techniques, including multiple planar reformation, maximum intensity projection, volume rendering technique, were compared.Results All of the CTPA images were satisfactory except one patient with severe right ventricular dysfunction in group B. The densities of PAT for group A and B were 374.7 HU ±89.5 (range,278.3～606.6 HU),403.8 HU±115.0 (range,288.6～698.5 HU) respectively. The densities of RLPV for group A and B were 287.7 HU±47.0 (range,235.4～413.5HU), 160.0 HU±51.9(range,62.3～238.4 HU) respectively. The displaying ratios of the 6th pulmonary artery for group A and B were 85.0%,80% respectively. The density of PAT and the displaying ratios of the 6th pulmonary artery showed no statistical significance, however the density of RLFV was significant difference between these two groups. There were its own advantages among different post-processing technique in displaying different type of embolism.Conclusion CTPA with triggering position located at SVC can decrease the dose of contrast medium and improve the quality of images. Combination the different post-processing techniques can display the embolism better and improve the accuracy of diagnosis.Objective The aim of the study is to investigate the diagnostic and applicable value of dual energy pulmonary perfusion diagnosis of PE using dual source CT (DSCT).Materials and Methods Seventy-eight consecutive patients who suspected PE underwent CT angiography (CTA) with the dual-energy technique on a DSCT scanner. The same data was transferred to Siemens workstation and post-processed to obtain the CTPA and perfusion blood volume (PBV) images. The quality and category of PBV image were evaluated by two radiologists. The quality of PBV image was defined four levels and the category of PBV image was divided into four types. The consistency of the two readers on image quality scoring and perfusion defect typing was tested with a kappa coefficient. The two readers also reviewed for the presence, localization and extent of PE, and the presence of changes in the lung parenchyma. The correlation between CTPA and PBV images was analyzed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of PBV images for the diagnosis of PE were calculated. Weighted Kappa values were calculated to evaluate the consistency between two readers.Results The scanning time, dose of contrast medium and effective radiation dose of CTPA were 6.8 s±1.2 (range 4.9～11.9 s),38 ml±7 (30-60 ml),1.3 mSv±0.1 (range 1.1～1.4 mSv) respectively. The ranking of image quality and scale for PBV were very good agreement between the two readers, the K value was 0.87,0.80,respectively,P<0.01.The sensitivity, specificity, PPV, and NPV of PVB for diagnosis of PE were 95.3%,56.4%,70.7%,91.2%, respectively. The sensitivity and specificity were 100% for the patients who had completely blokage.Conclusion The dual energy perfusion image using DSCT can show the pulmonary perfusion status and detect the pulmonary perfusion abnormalities that correspond to embolic vessel occlusion. The PBV images have high sensitivity and relatively low specificity to diagnose the PE without increasing the scanning time, dose of the contrast medium and radiation dose. Objective To prospectively investigate the correlation between CT angiographic clot load (CTACL) score, pulmonary perfusion defect (PPD) score and the global right ventricular function in the assessment of the PE severity.Materials and Methods One hundred and seven patients who suspected PE underwent DSCT scan. Forty-nine patients of them were diagnosed with PE and included in the study. The data from dual energy scanning protocol was transferred to Siemens workstation and the post-processing was performed with it to obtain the CTPA and PBV images. The data from ECG-gated coronary angiography scanning protocol was used for right ventricular function analysis. Two radiologists evaluated the CTACL and PPD scores according to the Qanadli and Chae methods respectively and their results were in consensus. At the same time, we assessed the correlation between the global right ventricular function and the cardiovascular parameters, which include the diameter of the PAT, the short axis diameter ratio of RV/LV at 4-chamber view and the reflux of contrast medium into inferior vena cava (IVC).Results The PPD score had a strong positive correlation with the CTACL score (r=0.72, p<0.001) and both scores in turn had a strong positive correlation with the right ventricular/left ventricular (RV/LV) diameter ratio (r=0.60, r=0.62,p<0.001). However, the PPD score had a strong negative correlation with ejection fraction (EF) (r=-0.63,p< 0.001) while the CTACL score had a low negative correlation with EF (r=-0.33, p=0.02). Between the RV/LV<1 group(n=35) and the RV/LV>1 group(n=14), the PPD score, CTACL score, pulmonary artery trunk (PAT) diameter, EF and reflux of inferior vena cava (IVC) were significantly different, all with p<0.001. The end-systolic volume (ESV)...